Industrial-rated circuit breakers are available having operating components that are designed for automatic assembly to provide cost improvement as well as improved operating efficiency. The precision alignment performed by the automated assembly equipment allows the operating components within the circuit breaker operation mechanism to be installed within very close operating tolerances. The operating mechanism assembly includes a pair of powerful operating springs that are overcentered for rapidly driving the movable contact arm and the attached movable contact away from the stationary fixed contact to interrupt the circuit current. The operating mechanism includes a cradle operator which engages a latch assembly to prevent the movable contact arm from being driven to its open position under the urgence of the charged operating springs. The compact latch assembly includes a primary and secondary latch operating within a common support structure.
As described within U.S. Pat. No. 5,089,795,the operating mechanism includes a crossbar unit that attaches the movable contact arm to the operating mechanism assembly. A force-resistant phenolic resin material having a solid steel core is used to fabricate the crossbar that connects the individual movable contact arms within the different poles in order that the contacts within each pole are opened and closed in unison. The metal staple and the crossbar vary in size to accommodate the various circuit breaker ampere ratings.
It would be economically advantageous to have a common-sized crossbar assembly that will accommodate a large range of circuit breaker ampere ratings and facilitate the assembly of the circuit breaker operating components.
One purpose of the invention is to provide a common crossbar assembly capable of being used within a large range of circuit breaker ampere ratings without deterring from the automatic assembly of the circuit breaker operating mechanism components.